I use whole disk encryption since around 2005 and didn't have any performance problem. The latest Truecrypt 7.0 uses AES-NI instructions in the i5 and i7 proce

I use whole disk encryption since around 2005 and didn't have any performance problem. The latest Truecrypt 7.0 uses AES-NI instructions in the i5 and i7 processors, which allegedly have 8x speed http://www.truecrypt.org/docs/?s=hardware-acceleration http://www.truecrypt.org/docs/?s=hardware-acceleration Go ahead and encrypt your whole drive, if there performance problems, you can easily de-encrypt it.